title: Human Mycobacterium tuberculosis CD8 T Cell Antigens/Epitopes Identified by a Proteomic Peptide Library.
abstract: Identification of CD8(+) T cell antigens/epitopes expressed by human pathogens with large genomes is especially challenging, yet necessary for vaccine development. Immunity to tuberculosis, a leading cause of mortality worldwide, requires CD8(+) T cell immunity, yet the repertoire of CD8 antigens/epitopes remains undefined. We used integrated computational and proteomic approaches to screen 10% of the Mycobacterium tuberculosis (Mtb) proteome for CD8 Mtb antigens. We designed a weighting schema based upon a Multiple Attribute Decision Making:framework to select 10% of the Mtb proteome with a high probability of containing CD8(+) T cell epitopes. We created a synthetic peptide library consisting of 15-mers overlapping by 11 aa. Using the interferon-γ ELISPOT assay and Mtb-infected dendritic cells as antigen presenting cells, we screened Mtb-specific CD8(+) T cell clones restricted by classical MHC class I molecules (MHC class Ia molecules), that were isolated from Mtb-infected humans, against this library. Three novel CD8 antigens were unambiguously identified: the EsxJ family (Rv1038c, Rv1197, Rv3620c, Rv2347c, Rv1792), PE9 (Rv1088), and PE_PGRS42 (Rv2487c). The epitopes are B5701-restricted EsxJ24-34, B3905-restricted PE953-67, and B3514-restricted PE_PGRS4248-56, respectively. The utility of peptide libraries in identifying unknown epitopes recognized by classically restricted CD8(+) T cells was confirmed, which can be applied to other intracellular pathogens with large size genomes. In addition, we identified three novel Mtb epitopes/antigens that may be evaluated for inclusion in vaccines and/or diagnostics for tuberculosis.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Oregon Health and Sciences University, Portland, Oregon ; Portland Veterans Administration Medical Center, Portland, Oregon.
authors.forename: David M
authors.initials: DM
authors.lastname: Lewinsohn
authors.forename: Gwendolyn M
authors.initials: GM
authors.lastname: Swarbrick
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Cansler
authors.forename: Megan D
authors.initials: MD
authors.lastname: Null
authors.forename: Veena
authors.initials: V
authors.lastname: Rajaraman
authors.forename: Marisa M
authors.initials: MM
authors.lastname: Frieder
authors.forename: David R
authors.initials: DR
authors.lastname: Sherman
authors.forename: Shannon
authors.initials: S
authors.lastname: McWeeney
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Lewinsohn
mesh_terms: D000595:Amino Acid Sequence; D016827:CD8 Antigens / Q000737:chemistry / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D058501:Enzyme-Linked Immunospot Assay; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000032:analysis* / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009000:Monocytes / Q000166:cytology; D009169:Mycobacterium tuberculosis / Q000502:physiology; D019151:Peptide Library; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D040901:Proteomics; D014376:Tuberculosis / Q000276:immunology / Q000382:microbiology / Q000473:pathology*
chemical_list: D016827:CD8 Antigens; D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D019151:Peptide Library; D010455:Peptides